The invention relates to a transport apparatus for transporting workpieces from one machining station to the subsequent machining station of a press, press line, simulator, or the like.
Where the manufacture of a workpiece calls for a plurality of work operations, such as cutting or shaping, then for economic production the necessary individual operations are carried out in a transfer press or press line, as they are known. The number of tools then corresponds to the number of work stages that are necessary for the manufacture. In the presses there are transport devices with which the workpieces are transported from one workstation to the next.
In the case of transfer presses or large-component transfer presses, the transport devices comprise gripper or load-bearing rails that extend through the entire length of the shaping machine. In order to transport the workpieces, the load-bearing rails are fitted with gripper or holding elements. In this case, a distinction is made, depending on the movement sequence, between a two-axis transfer fitted with suction crossmembers or a three-axis transfer fitted with gripper elements.
As an additional movement, pivoting in order to change the attitude of the component during the transport step may be required. This attitude change can also occur using an orientation station arranged between the shaping stages.
The transfer movement is initiated via cams that are forcibly synchronized with the ram drive via movement transmission elements. The manufacture of large-area components, in particular, has led to the development of large-component transfer presses of greater and greater dimensions, based on the shaping force and the transport paths. Tool spacings on the order of magnitude of 5000 mm are entirely normal nowadays, and therefore corresponding transport steps are also necessary.
As a result of this development, the masses to be accelerated and braked in the transfer systems are completely opposed to the low masses of the components to be transported. Since the transport step is to be executed in an extremely short time, in order to achieve the greatest possible number of press strokes and therefore output of components, the system must have a high speed and therefore also acceleration and retardation.
A further disadvantage is the rigid movement sequence which is predefined by the cam drives. The optimum utilization of the free spaces between the lower and upper tool during the ram stroke to transport the parts is not possible.
In order to avoid these indicated disadvantages, current new developments concern replacing the previous transfer system with a corresponding number of transfer systems arranged between the machining stages and equipped with discrete drives. Such an arrangement is disclosed in EP 0 672 480 B1. Transfer systems arranged on the uprights are equipped with a number of drives that, mechanically linked to the movement transmission means, transport the components. As a special feature, the system can be re-equipped both as a two-axis transfer with suction beams and as a three-axis transfer with grippers. However, this universal use requires corresponding structural complexity.
A transfer device disclosed in DE 100 42 991 A1 is also arranged in each upright area. The transport apparatus is embodied as an articulated arm and is thus designed such that favorable clearances are possible relative to the ram movement. The articulated arm can thus move between upper and lower tool with a relatively small opening stroke of the press ram carrying the upper tool for removing the part.
Disadvantageous in this arrangement is the space required for avoiding a collision between the ram and the transfer apparatus. In the prior art, a free space is required between the upright and the ram so that the transport apparatus can execute the pivot movement. This leads to pressing the larger dimensions transverse to the part transport direction required.
The object of the invention is to further develop an articulated arm transport apparatus such that no additional space is required for the articulated arm transport apparatus between the upright and the ram.